A conjugated diene-based rubber (e.g., styrene-butadiene copolymer) that is obtained using an emulsion polymerization method or a solution polymerization method has been known as rubber for producing an automotive tire. In recent years, an improvement in low fuel consumption performance (fuel efficiency) of automobiles has been increasingly desired, and various modified conjugated diene-based polymers have been proposed to meet such a demand. For example, a modified conjugated diene-based polymer obtained by modifying the terminal of a conjugated diene-based polymer using a compound that includes an amino group and an alkoxysilyl group has been proposed as rubber for producing an automotive tire (see Patent Document 1, for example). A modified conjugated diene-based polymer in which a silicon atom is bonded to a carbon atom that forms the main chain of the polymer, and an amino group is bonded to the silicon atom, and a modified conjugated diene-based polymer to which a benzene ring that includes an amino group is bonded, have also been proposed (see Patent Documents 2 and 3, for example).
Various additives may be added to a polymer composition used to produce an automotive tire in addition to the polymer component in order to improve various types of performance (e.g., tire strength and processability). Specifically, silica, carbon black, and the like may be added to the polymer composition in order to improve tire strength, and mineral oil, a compatibilizer, and the like may be added to the polymer composition in order to improve processability.